This invention relates to an artificial liver adapted for an artificial liver supplementing apparatus used for subsidizing the function of the liver of a patient who has a liver disease such as a severe hepatitis and, more particularly, to an apparatus for freezing a liver piece to freeze a living liver so as to endure a preservation of the artificial liver for a long period of time and to be able to be used timely as required.
The applicant has invented the following invention and filed a patent application as a freezing method capable of enduring a preservation of a liver for a long period of time and allowing the liver to sufficiently perform the function of the liver at the time of thawing and using the liver.
The filed invention is a method of freezing a liver by cutting a liver removed from a human being or an animal, from which blood is removed into fine cubic pieces and freezing the liver pieces with helium gas.
It is confirmed that the frozen artificial liver obtained by the method of this prior invention could perform the excellent action of supplementing the function of the liver. This is because the liver was finely cut, different from the conventional liver which was sliced into thin large-sized piece, substantially all fine liver pieces out from the surface to the central interior of the liver can perform the function of the liver and helium gas is employed instead of liquid helium without using liquefied nitrogen gas.
More particularly, this is considered because the boiling point of the liquid helium is cryogenic, approx. -269.degree. C., the specific heat of the helium gas is 5.23 (J/g.C..degree.), which is approx. five times as compared with the nitrogen gas, with the result that the freezing velocity is very high such as 1000.degree. C./mm, and the tissue of the liver can be frozen without being destroyest by utilizing such high freezing velocity.